1. Field of the Invention
The present invention relates to a DNC operation system which causes a host computer (hereinafter referred to as the “host apparatus”) to successively send NC data to a numerical controller that controls the drive of machinery, and uses the transmitted NC data to perform operations of such machinery.
2. Description of the Related Art
A standard operation performed by a numerical controller is the system of registering the NC data in a storage device such as an SRAM or a DRAM that is built into the numerical controller, and thereby performing operations (hereinafter referred to as the “memory operation”). Nevertheless, pursuant to the high-precision of part shapes and the enlargement of parts, the size of NC data is increasing, and there is a problem in that the NC data cannot be registered in the storage device in the numerical controller, and demands for the direct numerical control (DNC) operation of performing operations while transmitting the NC data from the host apparatus are increasing.
Moreover, even if it is possible to register the NC data for creating one part in the storage device in the numerical controller, different large-capacity NC data is required for each part in order to perform a small lot production of many products, and there is a problem in that the NC data registered in the storage device in the numerical controller needs to be replaced as required, and there are demands for realizing the DNC operation with only the NC data that is registered in the storage device in the host apparatus.
Technologies of a conventional DNC operation system are now explained based on the first system shown in FIG. 17 and the second system shown in FIG. 18.
With the first system of the conventional DNC operation, NC data is transmitted unidirectionally from the host apparatus to the numerical controller, and the numerical controller merely analyzes and executes the received NC data in succession. Thus, operations are performed without registering the transmitted NC data in the storage device in the numerical controller (refer to, for example, Japanese Patent Application Laid-Open No. 1-195509).
Moreover, with the second system of the conventional DNC operation, since the transmitted NC data is registered in the storage device in the numerical controller in order to realize a sub program call to the NC data stored in the storage device in the host apparatus, a registration start command and a registration end command are inserted, the NC data is registered as a subprogram in the storage device in the numerical controller together with the execution of the NC data, and the sub program registered in the storage device in the numerical controller is repeatedly executed later (refer to, for example, Japanese Patent Application Laid-Open No. 1-230101).
Since the first system of the DNC operation performs operations without registering the transmitted NC data in the storage device in the numerical controller, it is not possible to register information (sequence number, NC data itself, and so on) for performing a repeat instruction or a branch instruction, and these instructions cannot be executed. Moreover, with a sub program call, while the sub program call registered in the storage device in the numerical controller can be performed, since there are no means for notifying the call information (program name, NC data information of the restoration destination, and so on) to the host apparatus, it is not possible to perform the sub program call that is registered in the storage device in the host apparatus.
Thus, with regard to the NC data to be transmitted from the host apparatus, NC data, in which the sub program call, the repeat instruction, and the branch instruction are all expanded therein, needs to be created for exclusive use in the DNC operation, and the NC data of a format that can be used in the memory operation cannot be used as is, and there are problems in that it is difficult to create such exclusive NC data and the size of the NC data will also increase.
With the second system, the numerical controller needs to internally comprise a storage device for registering the transmitted NC data, and, as with the first system, NC data for exclusive use in the DNC operation needs to be created, and the NC data of a format that can be used in the memory operation cannot be used as is, and there are problems in that it is difficult to create such exclusive NC data and the size of the NC data will also increase.